FIG. 1.
Conflicts between morphological classification and genetic relatedness in dsDNA-tailed bacteriophages. Although bacteriophages HK97 (70) and L5 (59) share very similar morphologies, including a long flexible tail, there are no genes or encoded proteins that are detectable as close homologues. In contrast, bacteriophage P22 (132) has substantial numbers of genes in common with HK97; genetic differences lead to different tail morphologies, which led to classification into two distinct families. Proteins shared between HK97 and P22 exhibit BLASTP (4, 5) E values between 10−16 and 10−101; BLASTP E values for comparisons with L5 proteins failed to reveal matches with significance values lower than 100.